Hardware definition method including determining whether to implement a function as hardware or software

ABSTRACT

A hardware definition system and method includes a computer processor analyzing software function modules of a software program, and generating, for each of at least a subset of the software function modules, and on the basis of the analyzing step, a respective setting indicating whether the respective function module is to be implemented as a respective hardware module or as a software module executed on a hardware module defined in a hardware module library.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patent application Ser. No. 12/087,916, filed on Dec. 2, 2008, which is the National Stage of International Patent Application Serial No. PCT/EP2007/000380, filed on Jan. 17, 2007, the entire contents of each of which are expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a preferably reconfigurable architecture, or a preferably partially reconfigurable architecture, and a method for programming a cell element field, the elements of the field being able to execute a number of different functions, in particular such a multitude of functions that an all-purpose processor is obtained.

BACKGROUND INFORMATION

A method according the related art with respect to a design flow is shown in FIG. 1. FIG. 1 shows a known method of creating and programming a reconfigurable architecture in the sense of the remarks below. The figure shows on the right that a library containing modules for a larger chip is provided, which concerns, among other things, an ALU-PAE definition, a RAM-PAE definition etc. As required and specified, these different definitions are combined in an XPP generator and afterwards a synthesis is performed for the output obtained from the XPP generator in order to generate a mask set for the synthesized hardware on the basis of the result of the synthesis such that a chip may be produced.

The left side of the diagram shows a library for a number of programs (software parts) in a language such as NML, this special language being known from other publications of the applicant. Then a program is written by using such library software parts, it being obviously possible to use additionally and/or exclusively also software parts not contained in the library. The program is then compiled, compiling here being understood to include also placing and routing, as required. For this purpose, the compiler needs information that refers to the actual target hardware design. The compiler also has such information. The configuration(s) generated by the compiler are than made to run on the hardware as run time configuration.

It has also already been proposed (WO 2004/114166) to provide a so-called bottom-up approach in hardware design, an integrated circuit development system having been provided, which included a description library of a multitude of hardware objects, which are each structured to operate on message packets, each object being intended to have relatively similar electrical load characteristics; and the integrated circuit development system further including a modeler, which refers to the library and is to be structured to accept an instruction that creates an instantiation of one of the descriptions and to accept a command that combines two or more of the created instantiations with one another. The laborious programming of this known method of instantiated hardware objects then provides for a collection of software objects to be accepted which are themselves to be abstractions of the instantiated hardware objects, each software object being intended to include a list of hardware objects that are used in the software object as well as a list of rules for combining the listed hardware objects and an instruction file that is to be loaded into the listed hardware objects; a description of the collection of physically instantiated hardware objects then having to be accepted; an identifier having to be allocated to each of the physically instantiated hardware objects from the list of hardware objects and an initialization file having to be created for the collection of physically instantiated hardware objects by using the identifier in order to replace symbolic information in the instruction files. The last-mentioned technique as shown in WO 2004/114166 is disadvantageous particularly because of the fact that it can neither be assumed with absolute reliability that a hardware-software isomorphism is actually given and not merely claimed, and because in addition the applications designed in accordance with the system must often provide for an excess of unnecessary hardware on a silicon chip. At the same time there is no assurance that in the known procedure according to WO 2004/114166 an optimal execution speed of the hardware objects tied together from predefined, invariable hardware modules is realized.

Furthermore, in the cited related art as shown in WO 2004/114166, it remains necessary for hardware engineers to design the hardware. It is not possible to leave the construction of a chip for a dedicated application to the programmer of the dedicated application entirely or at least largely.

SUMMARY

In the present application, a reconfigurable architecture is understood in the broadest sense as an architecture in which at least one of the elements processing, storing and/or transmitting cross-linkages of data is itself modifiable; in a preferred variant, the term reconfigurable architecture being understood, without this being referenced each time, as a dynamically reconfigurable architecture, unless the respective semantic context indicates otherwise. In this connection, dynamic can refer to the capability of reconfiguration occurring at a speed that allows for a complete and/or partial reconfiguration at run time; the reconfiguration may thus occur for all cell elements, connecting elements etc. of a field, only for a subgroup of a field and/or for an individual element of the field. The reconfiguration may be induced, reference being made here for disclosure purposes to earlier patent documents of the applicant which are all incorporated to their full extent, e.g., by a possibly separately built up and/or pre-loaded central entity, by an adjacent cell and/or a cell within the element itself, which determines in the course of the data processing performed by it that subsequently another or additional data processing is required prior to or during the transmission and/or output of the data to another cell or outside the cell element field. A reconfiguration of elements lying upstream in the data path may also be brought about. The reconfiguration may be forced from the outside, i.e., outside of the field, and/or from inside and/or may be requested. Reconfiguration information is transmittable over separate reconfiguration lines, (data) buses and/or in direction connection from cell to cell.

The direct data connection from cell to cell may occur alternatively and/or additionally to an interconnection of multiple cells by connection to longer regions stretching over extended parts of the field and/or by a reconfiguration entity and/or external units such as data memories, data sources and/or data receivers. Such data receivers or data sources may be, for example, displays, data interfaces, external (host) processors, co-processors, microcontrollers and/or chip-integrated sequencer units and the like.

Reconfiguration information may, e.g., also be transmitted together with the data, e.g., also interested in data words of a longer data packet, it being in any event possible for the data exchange between the cell elements to occur preferably in an asynchronous manner. The transmission of configuration data from cell to cell may occur by transmitting actual configuration words for configuring a configurable cell element and/or by transmitting triggers, in particular in trigger vector form, a selection being made by these triggers between a plurality of configurations still to be fed in and/or are already fed in for the trigger vector target receiver cell element.

It is preferred, but not absolutely necessary for the purposes of the present application, if at least one, preferably multiple configurations are stored for current and/or subsequent processing in or at the cell elements, it being possible to provide either a configuration memory in each cell and/or for a group of cells as known per se from the earlier patent documents of the applicant.

Reference should be made to hierarchical structures, which may be established by and for processor fields of the present kind, be it for configuration data and/or data to be processed. It should be mentioned that in a data stream, trigger vectors may also be interposed in order to select between a plurality of different configurations, in particular configurations stored in advance, in the manner of a configuration ID. If, which is regarded as possible, several configurations are executable on one configurable cell element in a time-blending manner, as is provided for example in PCT/EP 02/02402 (PACT25/PCTE), all originating from the present applicant, then it may be possible in a preferred manner, to transmit along to the cell elements even in the data transmission information that relates to the association of a data packet with a certain task to be processed. With respect to these identifying specifications to be transmitted along with the data, reference is made to PCT/EP 02/02403 (PACT18/PCT), where particularly the explanations regarding APID should be compared, as well as in PCT/EP 02/10572 (PACT31/PCToe), where the explanations regarding CONFIGID should be compared. As far as the cell elements are concerned, it is per se possible that a currently considered reconfigurable architecture, for which a specific program is to be compiled, is a (fully) homogeneous field, in which for example as in the known XPP of the applicant a plurality of cells having in particular segmented buses in between are provided, it being possible, but not absolutely necessary, for the cells to be ALUs, in part having an extended range of function (EALUs), compare PCT/DE 97/02949 (PACT02/PCT), and (multi-stage) register units coupled to the input and output buses being possibly provided on both sides of the ALU, compare, e.g., FREG, BREC in PCT/EP 01/11299 (PACT22a/PCT), as well as respective refinements in other patent documents of the applicant. Furthermore, reference is made in this regard to input-output registers in front of the ALU itself, which under a different name are also found in other writings of the applicant.

For this purpose, the communication of the cell elements is preferably subjected to protocols such as the applicant has already described in connection with the XPP architecture.

Mention should be made in particular of the RDY/ACK protocol, the RDY/ABLE protocol from PCT/DE 03/00489 (PACT16/PCTD) as well as the additional protocols described there such as CREDIT protocols etc., e.g., protocols having a reject option. As applicant has pointed out in earlier applications, possibly received, but no longer needed, data packets may be discarded. Here mention should be made only by way of example of PCT/EP 2004/003603 (PACT50/PCTE), which is likewise in its full extent relevant also for other purposes, such as for application purposes with respect to the reconfigurable architecture for instance in connection with hyperthreading, processor-coupling etc., and which for disclosure purposes is to be regarded as incorporated in its full extent.

The cell elements may take the form of and/or include in particular ALU-PAEs, EALU-PAEs, RAM-PAEs, RAM+ALU-PAEs, function-folding PAEs (see DE 10 2005 005 766.7, DE 10 2005 010 846.6, DE 10 2005 014 860.3, DE 10 2005 023 785.1, EP 05 005 832.0, EP 05 019 296.2, EP 05 020 297.7, EP 05 020 772.9, and (PACT62 ff)), graph-folding PAEs, sequencer structures connected via command lines as well as PAEs, which may have, in addition to a configurable or adjustable unit such as an ALU, a memory such as a circular buffer and the like, in particular those having several pointers etc., also parts firmly defined once in their function, for example FPGA-like logic circuits that are defined, FPGA-like groups that are reconfigurable only seldom and preferably without recourse to preferred, in particular faster configuration methods and/or logic circuits fixed in their functionality such as ASICs, which may be used for example for certain I/O protocols such as RS232, LAIN, VGA, XVGA, DVI, USB, S/PDIF, Firewire, RAMBUS etc.

Furthermore, using the ASIC-like logic circuits, which may belong to the cell elements, it is possible to fall back on fixed functions, for example ASIC-like programmed DCT algorithms, FIR filters or IIR filters, VITERBI algorithms etc., which may be of significance for various applications such as in general purpose processors, general purpose co-processors, microcontrollers, sequencers, image editing and/or image processing such as for HDTV, cameras, base stations, mobile telephones, radio receivers (software-defined radio), smart antennas, CODECs and/or parts for these.

In order to be able to use such structures and methods of structure operation, the corresponding hardware must now be designed and data processing processes capable of being executed on this hardware must be defined.

Experience has shown that, as discussed abover with respect to FIG. 1, it is already possible without problem to design hardware having the aforementioned architecture, protocols etc. and to write programs for it. As far as programs for the architecture are concerned, reference is made in particular to the NML language and the documentation, manuals and general descriptions existing for it. It should be mentioned that programming languages are known per se and are optionally applicable to the specific architecture as well. BASIC, LISP, COBOL, PL-M, ADA, ALGOL, FORTRAN, BASH, TCL, but also JAVA, C in various dialects such as C++, PASCAL, OBERON, EIFFEL, PERL, A, B, XML, UML are example possibly relevant high level programming languages.

Embodiments of the present invention make possible at least partial improvements in the design and/or with respect to the usability of structures and architectures mentioned at the outset.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a procedure according to the related art.

FIG. 2 shows an improved method in accordance with the present invention for creating and/or programming hardware.

FIG. 3 shows a parameterizable hyper-PAE according to an example embodiment of the present invention.

FIG. 4 shows insertion and removal of registers according to an example embodiment of the present invention.

FIG. 5 a shows a connection of an element array to a hardware module by way of FIFO memories according to an example embodiment of the present invention.

FIG. 5 b shows a connection of an element array to a hardware module with RAM memories as coupling elements according to an example embodiment of the present invention.

FIG. 6 a shows a connection of an element array to a hardware module by way of FIFO memories, where trigger vectors are transmitted, according to an example embodiment of the present invention.

FIG. 7 shows a coupling arrangement according to an example embodiment of the present invention.

FIGS. 8 a-8 d show spatial arrangements of hardware modules with respect to an NW field, according to an example embodiment of the present invention.

FIG. 9 shows various interconnections between hardware modules and between the hardware modules and parts of an element array, according to an example embodiment of the present invention.

DETAILED DESCRIPTION

As is yet to be explained below, FIG. 2 shows essentially parts of the design flow as is also known in FIG. 1 from the related art, but it supplements and extends or modifies it in an inventive manner. As will become apparent and be explained below, the following is of particular importance in this regard.

First, a high level language program is provided, in which initially no reference needs to be made to actual hardware characteristics. This program may be written in the conventional high level languages such as C++, JAVA, MATLAB etc. Thus, programming is performed in abstraction from any hardware, ergo at this point one preferably, but not necessarily, uses an entirely, at least partially hardware-abstracted language. These hardware-abstracted programs or this hardware-abstracted program is then translated as known per se preferably with reference to a quasi-maximally free hyperset, that is, a superset of possible hardware objects, which for individual objects may include a plurality of variants, these variants also for example, which is preferred, possibly differing from one another in a manner determinable by parameters in one or in multiple characteristics. When the hardware-abstracted high level language program is translated with reference to a quasi-maximally free hyperset of possible hardware structures etc., for the purpose of which a transformation compiler is used, then for this purpose one may fall back on a multitude of PAEs parameterized for this hyperset and similar suitable modules stored in a software library. The modules in the library may be intended for parameterized or still parameterizable elements of the hyperset, and, as the translation described above as performed by the transformation compiler, may occur both by machine coding as well as if desired entirely and/or partially manual coding. It should be mentioned that the use of modules in machine and/or manual translation is not absolutely necessary.

The parameterization may be performed interactively by a programmer, in particular by interaction with a place-and-route tool, but may also be suggested by the latter, possibly even in a fully automatic manner, and possibly only be confirmed and/or stipulated without confirmation. Alternatively, heuristic methods are possible as well, possibly even interactively and/or by open-loop and closed-loop control of a place-and-route tool. In heuristic methods, an iterative procedure using the place-and-route tool or another tool in the programming and hardware definition environment may be performed. It should be pointed out that such iterations may occur manually, semi-automatically and/or alternatively and particularly preferentially in a fully automatic manner.

With the heuristic, SETPOINT variables may be specified for this purpose, which are to be reached by the iteration, by trial and error for example. In this connection, for purposes of disclosure, explicit reference should be made to the methods of “simulated annealing.”

In addition to methods of simulated annealing, obviously, evolutionary methods such as genetic algorithms may be readily used as well.

In this connection, quasi-maximally free incidentally means for the hyperset that the number of limitations to generally available objects is as low as possible, that is, that as many degrees of freedom as possible remain. Notwithstanding the demand for as many degrees of freedom as possible, however, limitations may be necessitated by certain factors such as, e.g., the constructability of modules in the target semiconductor implementation, which is why the term “quasi-” maximally free is chosen. Incidentally, it should be pointed out that in certain cases the quasi-maximally free hyperset needs to contain only one PAE, which then however must be largely and in many parameters parameterizable, from which by parameterization many mutually distinct PAEs are derivable.

The final result is thus a program from a multitude of functional blocks, which are indicated in FIG. 2 as f(n) for different n.

On the basis of this program, which was already generated with recourse to hyperset elements from the high level language program and was thus generated in a manner according to the present invention, novel with respect to the related art and in a manner regarded as in accordance with patent for itself, a further improvement may now be achieved. First it is possible (proceeding to the right in the illustration) to select certain of the program parts for processing on the hardware later executing the program not by elements provided for general purposes, selected from the hyperset and determined by parameterization etc. entirely in their hardware construction, which, programmable or configurable, are available also for quasi any other task to be processed in the reconfigurable field, but to be implemented individually and/or jointly in a hardware system specialized and optimized or optimizable by dedication. In FIG. 2, program parts f(3), f(n), f(n-2) are selected for this purpose. Typically, such program parts may and will be configurations or configuration parts or an individual configuration for an XPP field or the like, which is composed of an at least partially reconfigurable set of elements such as ALU-PAEs, graph-folding PAEs, function PAEs, MAC PAEs, RAM PAEs, ROP PAEs and/or input-output PAEs, which are described in the hyperset or describable by the latter, in particular completely describable by parameterization. The selection of the type of modules to be implemented may occur in various ways; the following possibilities being mentioned only by way of example, it being obvious that it is possible and preferred in a practically preferred embodiment of the present invention not to fall back exclusively on a single one of the possibilities, but rather to provide multiple or all of the possibilities for simultaneous or successive implementation as hardware module of program parts:

-   -   selection of program parts by hand, which may be done         particularly by inserting suitable text passages in the program         code such as, e.g., by inserting control characters;     -   selection of those program parts that occur and/or must be         executed particularly frequently in the entire program code or         in a multitude of program codes, which are to be executed         independently of one another on the hardware to be produced,         will probably come to be executed, that is, a selection         according to execution time and/or execution frequency;     -   modules, from which one is able to ascertain that with respect         to other elements they are otherwise executable only with         difficulty or at a higher clock frequency, that is, program         parts that prove to be critical with respect to performance; the         selection of such program parts may be preferred so as to be         able to execute certain program parts on a certain piece of         hardware at all;     -   selection of program parts, which otherwise would generate a         particularly high power loss on the hardware to be produced;     -   program parts, which could result in a particularly high surface         area requirement of the hardware chip;     -   selection of program parts according to heuristic methods, which         allows, particularly on the basis of the program code, for         a—even for itself possible—parameterization; and     -   selection of program parts by profiling or comparable         techniques; it may be provided either to identify on the basis         of a source code analysis those parts for which dedicated         hardware modules are particularly suitable, for example with a         view to the above-mentioned parameters with respect to         executability, implementability etc. Alternatively and/or         additionally it is possible to perform a profiling during the         execution of programs. For this purpose, an analysis may be made         as to which program parts, subprogram parts, configurations,         configuration parts etc. are subject to a particularly frequent         execution, are performance-critical, surface area-critical,         require many and/or long memory accesses, are particularly         frequently used in various configurations etc. The advantage of         such a profiling lies in the fact that for typical applications         that call up a multitude of programs, for example the         application of a processor as a general purpose processor on a         server, a laptop or a workstation, processors, co-processors and         the like may be defined that are optimized for a or typical         user(s). To be sure, it is possible to perform such a profiling         on a simulator as well, but the particular advantage of the         present technique of the top-down approach is that initially an         already highly performing chip, which is thus specifying real         time conditions, may be used, which does not compromise a user         whose profile is to be detected, is made available. Thus, by         using the target architecture, it is possible to detect how it         may best be subjected to a design change process without         performance losses, but rather while improving the performance         with respect to critical parameters. It is pointed out that,         apart from the circuits described here, corresponding precisely         to the later desired architecture by the definition of hardware         modules, the idea of starting from the actual target         architecture for defining modified circuits by selecting         particular program parts and described definition of the         hardware parts is regarded as inventive for itself; in         particular, the submission of partial applications and the like         is reserved for this purpose and/or for parts of these aspects.         Reference should be made to the possibility of performing a         successive processor improvement by transmitting a multitude of         profiles to a central unit, e.g., a processor manufacturing         firm, in particular by transmission over the Internet. This may         be used, e.g., for standard programs and for other processors.

In this connection, it should be mentioned incidentally that by taking the data obtained by profiling a manual selection may be made and/or an automated selection.

It should be mentioned that in the selection it is not necessary always to pay attention only to one parameter. Rather, it may be possible, for example by recourse to methods of fuzzy logic, to take into account multiple or all of the above-mentioned influencing parameters, particularly with a suitable weighting and/or in an nonlinear manner. The selected program parts are initially on the already known PAEs existing in the hyperset, which incidentally may include, in addition to the previously mentioned PAEs, also PAEs that are made up of a combination of the functionalities of the above-listed PAEs, that is, for example, a parameterizable or parameterized PAE having a parameterizable set of ALUs of parameterizable bit width and parameterizable range of function, it being possible for this PAE to include additional graph-folding, parameterizable elements, just as function-folding, parameterizable elements parameterizable with respect to the bit width for example and/or in particular parameterizable memory areas having pointers and/or command-control line of one or multiple ALUs, or other data-modifying parts in the PAE, in order to implement sequencers or microprocessors, input-output elements and the like.

An example of a still parameterizable hyper-PAE is shown in FIG. 3. There one finds various parameterizable units such as, e.g., bus inputs having m inputs, m representing a parameter, that is, m different operands may be supplied to one PAE. The buses are respectively k bits wide, k in turn representing a parameter, and n different buses are provided, from which the m different inputs are picked off. The total number of buses, n, also represents a parameter. Within the PAE, different operand-combining units are then shown by way of example, in the exemplary embodiment shown in FIG. 3 for example a divider having a combinatorial network, a multiplier, an ALU stage, a Boolean logic, a barrel shifter stage as well as a floating point unit. It should be pointed out that the aforementioned units in turn are parameterizable, for example with respect to the operand width, that is, they may be, e.g., 8 bit, 16 bit, 32 bit or 64 bit stages or obviously stages of other bit width as well, it being additionally possible for the range of function, for example of the ALU, the floating point unit etc. to be defined via parameters. It should be pointed out that for reasons of simplicity of the drawing certain, omitted elements, which possibly may also be provided in a hyper PAE such as sequencer units, function-folding PAEs, compare PCT/EP 03/09957, may be provided. It should be mentioned that memories of parameterizable width and depth may also be provided etc. In this connection, reference is made in particular to the previous applications of the present applicant, in which a multiplicity of different logic elements such as also FPGA-like structures, SIMD units etc. for PAEs are disclosed, this disclosure being incorporated in its full extent.

Regarding the parameterizable range of function, the flow point unit may be, only by way of example, a floating point unit that is capable of at least one, preferably several of the following combinations in the still parameterizable definition: multiplication, addition, subtraction, division, floating point combination, look-up tables, possibly having an interpolation option for certain functions such as trigonometric functions (sine, cosine, tangent), sequential calculations as for Taylor series, it being possible for special hardware to be provided for certain approximations/interpolations and it being possible preferably in addition for a parameterization of the floating point unit to be provided with respect to the data word width in the mantissa and/or exponent.

A parameterizable library for such a hyper PAE may have recourse, for example, to a procedure in which so-called ifdef constructs are used. These supply certain program segments to a translation (in hardware circuits, which must be actually provided on a chip) only if corresponding definitions are provided for this, for example by specifying the parameters, for example the range of function. It should be mentioned that this is also possible for variables and elements of the hyper PAE such as the configuration registers specified also at varying depth, possibly the protocols (compare RDY/ACK, credit protocols, RDY/ABLE etc.) capable of being implemented on a PAE, just as the parameterization of an output, different multiplexer stages in a PAE etc.

In order to achieve the desired improvements either with respect to some of the previously selected critical criteria such as power consumption, surface area efficiency or execution performance and/or a particularly great improvement in at least one of the areas combined with at best a partial improvement of other areas or a complete disregard of the same, for example, if in high performance-critical program parts, power and/or surface area do not matter, a preferably automatic and/or partially automatic converter step is now executed in a preferred embodiment. This is indicated in the figure as NML2V and represents a converter step by which a hardware language description is determined for the program parts that were selected, possibly by taking into account the reason for the selection. In light of the fact that the program parts for the hardware modules were selected with reference to one or more elements in a hyperset, it is possible to find an identical translation, that is, it is ensured that no errors occur in the conversion into a hardware-describing code such as VERILOG, which, if this is desired, may be confirmable by intermediately executable simulation steps. Thus, one first obtains a hardware-describing code, e.g., a VERILOG code, which has the corresponding functionality of the parameterized PAE in the investigated configuration(s).

Surprisingly, the use of hyper PAEs in the definition of the program parts, which are then used for implementing hardware modules, proves to be nondisruptive for the converter to hardware code. The reason for this is that certain of the parameterizable characteristics such as the bit width of the PAE, for example, must already be determined when determining the actual program for the transformation compiler, while other characteristics such as the actual ranges of function for example, that is, for example the provision of a divider stage, a multiplier stage, and adder stage and/or a subtracter stage in an ALU-PAE do not yet have to be defined. In other words, simultaneously with the transformation compilation the quasi-maximally free hyperset is reduced to a parameterized and/or partially parameterized hypersubset, in particular fewer degrees of freedom being specified, that is, no modification being required. In this instance, the bus widths to the cells may already be defined for example. It should be mentioned that the already defined parameters, which were defined in the transformation compilation for example, are made available to the NML-to-VERILOG converter or, more generally, to the hardware language description-generating converter, which may be done by corresponding indications on the program parts, for example in the form of comment lines and/or by data separated from the actual program part. The transformation compiler is thus designed for the generation of parameterization information of hardware on which it is to be based. In contrast to conventional compilers, hardware-describing code, that is, code describing degrees of freedom, is also generated.

The program parts, for which a hardware module is to be implemented in an optimized manner, now not only have parameters defined with respect to the PAEs, but rather it is at the same time clear in which configuration a certain PAE is to be operated in the program part that is to be converted to a hardware module. This configuration now has the consequence that it is, if applicable, immediately clear that certain parts of the PAE are not used, which is the case for example if in the transformation compiler a floating point unit must still be provided for other program parts, but no floating point operations are required in a currently considered program part that is to be translated into a hardware module. The configuration that is defined for purposes of the present consideration (bearing in mind that multiple configurations to be processed successively may be present in the PAE for sequencer-like PAEs or PAEs operated in a sequencer-like manner) thus indicates that certain units are not required and it is then possible to ascertain that for example a multiplexer connected downstream from an operand combination stage, which is used to select which operand combination unit should set its output or outputs to an output region, is dispensable or partially dispensable. The multiplexer typically situated behind the multiple operand combination units of a typical PAE may thus as a rule be readily simplified in a given hardware module. An invention per se is likewise seen in the removal of multiplexer stages and/or complete multiplexer units in the determination of hardware modules with recourse to hyper PAEs or a quasi-maximally free set of hyper PAEs. It should be mentioned that the removal of elements not required in a configuration to be executed in a PAE may occur by the NML2V converter, that is, in the isomorphous hardware simplification means, and/or that the selection of hardware elements to be removed as not required may also be performed by way of a synthesis. Incidentally, it should be pointed out that in the hardware module or the parts intended for the latter the configuration register does not necessarily have to contain only one constant value as was, e.g., depicted for reasons of better illustration. Rather, particularly if wave-like changes or reconfigurations of the operating mode and/or conditional changes of the operating mode of an individual element are required for the hardware module, for example as a function of data processing stages above or below, multiple possible configurations may be stored in the configuration register. The selection among such previously stored configurations, which are disclosed by the applicant in other applications, is pointed out in a manner fully incorporating by reference, compare in particular, although not exclusively, PCT/DE 98/00334 (PACT08/PCT). Incidentally, it should also be pointed out that not only trigger vectors etc. are transmittable, but possibly, within the hardware module and/or from outside in an accordingly limited range of function, also data are transmittable directly to a unit, which may be regarded as configuration data, work instructions (commands etc.) and/or which may contain respective instructions, in particular set between operands. Incidentally, it should be pointed out that the hardware module may also be defined in such a way that freely definable configurations are still executable on the defined hardware module, these freely definable configurations then in each individual element accessing a reduced set of functions and/or a limited connectivity, for example only with respect to next-neighbor connections instead of global bus connection extending over many cells being possibly provided between the individual elements of the thus defined hardware module, whereas nevertheless a multidimensional, that is, also possibly clearly more than two-dimensional connectivity and/or a toroidal, even multi-dimensionally toroidal connectivity is feasible.

The hardware description code of the NMLV2 converter thus generated preferably automatically is now still optimized in a particularly preferred variant of the present invention. The aim of this optimization is on the one hand to allow for the elimination of the registers, combination units etc. in a parameterizable PAE that are not required for the respective functionality; reference being made in this connection to the earlier applications of the present applicant, compare PCT/EP 03/08080 (PACT30/PCTE) and PCT/EP 03/08081 (PACT33/PCTE). These provided for a configuration of a field or of an individual PAE to be defined once by the use of fuses, that is, breakable elements and the like in order to allow for a problem-free construction of chips having ASIC functionality without the requirement of a mask construction for each ASIC embodiment; although in this previously known variant possibly not required elements of functionality remained in the ALU or another unit of a PAE. If, for example, a PAE having an ALU, which included a subtracter, a divider, an adder and a multiplier, was configured in a fixed manner in order to provide an adder, then the silicon surface area used for producing the multiplier had to be provided nevertheless. The present application and invention among other things in one of its aspects aims to avoid this, which contributes toward a reduction of the size and thus possibly also of the execution speeds of a dedicated hardware area. The corresponding changes in the parameterizable and already partially parameterized hyper PAE take place in a retiming stage, in which initially unnecessary registers are removed. The removal of the registers first results in a decapsulation of functional parts previously encapsulated by the use of the PAE definition. This is by no means critical, however. On the contrary, in the case of a suitably intelligent design chain, it is rather very advantageous.

The design chain hereby provided according to the present invention inherently features the intelligent layout, which renders obsolete the complex encapsulation required in the related art, for example by input-output FIFOs and/or registers, which are practically controllable only via suitable protocols such as RDY/ACK protocols. For this purpose, e.g., initially the internal registers are removed, that is, the registers situated between the considered cells at their mutual junctions. The removal of the registers, however, does not occur blindly for all registers, but rather there is a preferably readily automated selection of registers that are removable or that must remain in the piece of hardware. First, constants should remain in the piece of hardware. Further, it is strongly preferred if registers for preloading values (PRELOAD registers) are not removed. Additional registers are initially not required in a given implementation of the method.

This obviously changes the timing behavior or the overall system. Now, the present invention provides for the registers to be removed nevertheless, but for a synthesis step to be performed in order to ensure a correct timing of the data processing by the considered piece of hardware. Preferably, therefore, a synthesis step is performed according to the present invention. This also applies to the inputs/outputs of the hardware module to be constructed.

It should be pointed out that by and for suitable logging bus-internal registers may readily be used, that a feeding-in/reading-out of data in RAM-PAEs having sufficient memory depth is possible and/or a reading-in/reading-out of data in the preload memory, if required at all, may occur, or the provision of input-output registers at the end and at the beginning of the piece of hardware, unless for example the long-familiar FORWARD-BACKWARD registers are also to be provided for purposes of use by other PAEs. In a preferred design, constant contents of RAMs are implemented by ROMs or mapped onto ROMs.

The removal of the registers will now change the timing behavior. Initially, the frequency behavior of the considered circuit to be provided may deteriorate, possibly even significantly. This may be compensated by again inserting registers in suitable places, which are either arranged according to fixed rules, for example by inserting less deep register stages in places where previously deeper register stages were provided, by inserting register stages of the same depth as those that were previously removed, or, particularly preferably, by considering the signal run times through the remaining hardware circuits in order to identify places at which registers are required to increase the frequency; one skilled in the art being able to perform such a procedure per se without deeper explanation.

It must further be kept in mind that, while the considered software part may be regarded as initially balanced, balancing is normally performed or could be performed by providing register stages between different data-processing functionality areas in or between the PAEs etc. The initial removal of the registers now impairs the possible or already given balance of the data-processing paths, which must be coupled at certain points. In another register insertion step, the attempt is now made either to arrange the registers already provided again in such a way that not only the possibly demanded and required frequency increase is obtained, but rather at the same time also a data run time balance is achieved. Thus an automatic balancing in the retiming means by register insertion is brought about by retiming only on the basis of program parts possibly to be made into hardware modules, in which it is pointed out that certain data paths are to be balanced against one another.

Something else has to be kept in mind as well when retiming: The hyper PAE, even in the case of a given parameterization, will normally still include functionalities that are not required in the hardware module. For example, it would be conceivable that a hardware module is written for a program part in which no divisions are required at all. In this case, a divider stage could be omitted in a PAE. A division now requires a certain delay, that is, a run time across the module. This will be significantly greater than for example the run time across an adder stage. The primarily given data run time balance of the parameterized or hyper PAE will be such that the run times of a divider stage are taken into account as well. If, however, in a hardware module at a certain point a divider stage is no longer required, which is discernible, then such non-required unit may and preferably will be removed from the PAE, which then changes the delay of the data run through the unit. The hardware module should also be adapted accordingly when retiming. Fundamentally, it should be pointed out that this is not absolutely necessary, however. A certain advantage is already obtained if between the individual stages of a hardware module composed of multiple hyper PAEs non-required register stages are removed. In the preferred case, however, non-required parts are also removed from the hyper PAEs, which may occur during the synthesis, for example, such as, e.g., the removal of a divider stage discussed above, other stages such as memory stage elements, multipliers, floating point units etc. being also removable, if indicated. This too may be taken into account when retiming. For this purpose, a synthesis is preferably performed, by which the timing behavior is analyzed in an automated manner in order then either automatically to insert registers in required places and/or to provide indications where a programmer should insert registers in order to ensure a proper timing behavior.

Incidentally, it should be pointed out that divider stages were mentioned above. With regard to this and to the removability of register it should be pointed out explicitly, although exemplarily, that on the one hand protocol-relevant and data communication-relevant registers may be provided in a module or array; such being readily removed at first. Precisely the division shows, however, that certain registers shall not and/or cannot be removed. The division may be implemented in two ways if a division stage to be provided in hardware is to be constructed. The first possibility provides for a combinatorial network, in which no registers are required. The second variant provides for a sequential division, in which a value is computed iteratively again and again, comparable to the manual computation of a division. In the latter case, intermediary results must be written into registers. These must not be removed when retiming since they are algorithmically required. The non-removal may be brought about, e.g., by indications in the hardware-defining code of the hyper PAE, which may lead to comments in a compiler code of the transformation compiler that are not required for actual program purposes. Alternatively and/or additionally, variants are conceivable, in which first a removal and subsequently a reinsertion may be performed.

In a particularly preferred variant, therefore, the hyper PAEs may be marked as to whether certain registers are algorithmically required such that they are not automatically removed in an initial removal of the registers. Alternatively and/or additionally, when removing superfluous registers, analyses may be performed to the effect that registers having a feedback to circuit regions located upstream of the data flow are not removed. For such registers are automatically algorithmically relevant registers. It should be pointed out that even algorithmically required registers are obviously removable if the algorithm with which they are associated is not executed; something that happens for example in the case of a sequential division generally provided in a hyper PAE if the division per se is not implemented in the hardware module to be constructed. Incidentally, it should be pointed out that feedbacks are implemented in the standard PAEs provided by the applicant by backward registers. If these are actually required in a given program part, it is advantageous not to remove them or not to remove them without verification and/or not to remove them completely.

If indicated, registers are then inserted with the retimer. It should be mentioned that it is in principle possible to insert the registers at any place in the hardware module, as required. In particular, if performance efficiency is the sole concern, then it is possible to insert register within a (parameterized) hyper PAE that is provided in the hardware module. It should be pointed out, however, that a simpler method of register insertion is obtained if on the interfaces between multiple hyper PAEs in the hardware module to be designed again those registers or a part of those registers are inserted, which were initially removed. The reason for this is to be seen in the fact that an optimum insertion in these places is possible for the reason that the entire starting definition of the hyper PAEs is selected to be such that an insertion is automatically possible in these places. Reference is made to FIG. 4, which shows how initially registers are removed for an only exemplarily pipeline-like, only exemplarily unbranched hardware module. These are shown as “removed registers” in a shaded manner. In the hyper PAEs, which are drawn upon in the parameterized faun of the hardware module description, these registers are the input/output protocol registers, that is, for example the FREG/BREG of the hyper PAEs. Alternatively it is possible to provide PAEs without FREG/BREG only with those registers that are provided in the direct coupling path of the ALUs and other logic elements for operand combination in the PAE in the connections to the buses as protocol registers. Reference is made in particular to OREG and PREG from PCT/DE 97/02949 (PACT02/PCT). The newly inserted registers, which ensure the balancing or the desired performance/surface area efficiency/latency following the removal of the shaded registers, are drawn in FIG. 4 by dashed lines and indicated as “inserted register” or for multi-stage registers as “inserted FIFO.”

It should be pointed out once more that the represented insertion of registers, FIFOs and the like between the predefined hyper PAEs not only simplifies the structural layout, but also facilitates the verification and calculation of the delay times across the circuits provided in the hardware module since the run time behavior etc. of the underlying elements may be assumed as well-known in the register removal step or the retiming step, which facilitates a possibly iterative approach to the retiming task. In addition, the insertion of registers between the previously used and underlying (parameterized) hyper PAEs is particularly surface area-efficient since, e.g., the use of general ALUs in the hyper PAEs would there require a multitude of registers even though the insertion would readily be possible there as well, for example in order to achieve particularly high frequencies. In addition, there is hardly a positive effect in a cut within an ALU or a PAE core.

Incidentally, it should be mentioned that it is readily possible to design a hardware module in such a way that it has to run at a different working frequency than that provided for an XPP field or another reconfigurable unit field. On the one hand, it is possible to select the frequencies to be lower, for example to reduce latencies, to reduce the surface area and/or to reduce the power consumption. For the sake of completeness, it should also be disclosed that for lowering the power consumption it is also possible, if indicated, to work with other hardware definitions such as for example different gate thicknesses of transistors in comparison to a reconfigurable, processor field to be likewise provided. As an alternative to the purely power-saving considerations, it is also possible in certain cases to design the hardware modules for a certain frequency, which may be advantageous especially if a particularly high data throughput is required in the hardware module and/or if highly computing-intensive tasks must be processed in it.

Incidentally, it should be pointed out that the register stages or FIFO stages to be inserted or to be newly introduced or reintroduced are usable not only with a view to, e.g., latencies, but rather also in order to restore a balance of data flow paths possibly destroyed by the initial removal of registers. It should be pointed out that initially after removing the registers a balanced data path automatically exists, but that possibly timing conditions are not maintained; and that then initially the timing behavior is restored by inserting additional registers, but that because of that the balance between the individual data paths may be disturbed. In order to restore the balance as well after having restored the timing conditions and timing requirements, recourse may be taken readily to the techniques for balancing from the related art, particularly to those stemming from the applicant, by using in particular precisely those algorithms to which recourse is taken also in the construction of compilers such as for an NML compiler for computing executable configurations. Reference is made in particular to the applications PCT/EP 02/10065 (PACT11/PCTE), PCT/EP 02/06865 (PACT20/PCTE), PCT/EP 03/00624 (PACT27/PCTE), PCT/EP 2004/009640 (PACT48/PCTE). In these applications suitable methods for balancing are described.

The output from the retimer is then a hardware code definitely executable by recourse to the hyper PAEs or elements of the quasi-maximally free hyperset, which is frequency-optimized and/or throughput-optimized through the retiming. In addition, the surface area is automatically optimized. The definition thus obtained of new hardware areas as hard modules may now be integrated into the XPP library. There are many possibilities for the thus determined hardware module functionalities to be integrated into and/or be connected to an XPP field or, more generally, a field of reconfigurable and/or partially reconfigurable elements. One possibility, for example, is to provide a complete PAE, which does not have an ALU or an individual sequencer as central functionality, but rather the specified hardware functionality of the hardware module. In this instance, it is particularly preferred if in such a PAE, as is provided in PCT/EP 01/08534 (PACT14/PCT), an outwardly identical geometry and in particular a connection geometry is provided, as in other PAEs of the field. This has the great advantage that the homogeneity of the field remains largely unimpaired. Alternatively and/or additionally, it is possible to achieve a connection without a corresponding consideration of form factors and the like, compare DE 102 36 269.6 and DE 102 38 172.0-53 (PACT36 and 36I), by setting the specific hardware modules next to the actual field. For this purpose, it is possible to provide for an integral manufacture and/or to manufacture the parts separately and then to let them communicate via buses, via RAMs and the like with the reconfigurable field, compare SOC technology etc.

Other possibilities of connection are described in the figures.

FIG. 5 a shows on the left a combination of an XPP field or an FPGA field with a hardware module of the present invention, the connection of the hardware module to the field occurring via FIFO memories in the input path and/or output path, preferably via FIFOs in both paths. By providing a FIFO memory between the or each hardware module of the present invention, a decoupling is already achieved in principle, which allows for a more independent procedure and a deviating timing etc. especially with respect to the processing speed.

It is particularly advantageous, however, if the exchanged data packets are given identification information in the form of a packet header or additional identification bits on each individual word or the like. In this manner it is possible, for example, to execute different tasks in a multithreading, hyperthreading, multitasking, timeslotted or other manner either with the hardware module and/or the XPP or FPGA field or another field and then, in spite of the comparatively loose coupling effected via the FIFOs, to ensure nevertheless that an exchanged data packet or data word undergoes the correct processing in the receiver, that is, in the hardware module or the XPP field or the like.

It should be mentioned that it is already helpful if identification information in the hardware module remains unchanged and/or is changed only in such a way that the associated data packet is processed in the manner provided following the return of the processing result to the receiver, that is, for example the XPP field, for example in that it is processed further using the correct configuration.

Alternatively and/or additionally it is possible, however, to co-transmit, in place of pure identification information and/or in addition to the latter, also control instructions or the like, in order to choose for example in marginally changeable hardware modules, whether an addition or a subtraction of consecutive operands is to be performed and the like. In this manner, an increased flexibility of programming all the way to self-modifying code may be achieved.

FIG. 5 b shows how for coupling a hardware module in the input path and/or output path it is possible to provide coupling elements in the form of RAM memories, in particular even of RAM PAEs, rather than in the form of FIFOs. This makes it possible in particular to provide respectively dedicated memory areas both for writing data from the field for the hardware module as well as when writing from the hardware module for the field, that is, when transferring data from the field to the hardware module on the one hand, and when (here:) returning results from the hardware module to the field on the other hand. This facilitates on the hand the handling of different configurations and on the other hand allows for example for prioritizations in that work, that is, reading and writing, is performed primarily and preferably in a first memory area, and only if a data processing has been performed sufficiently often in the first memory area and/or no data are present there, will recourse be taken to other memory areas and thus other tasks.

Incidentally, it should be mentioned that in those places in the present document where there is talk of data input from the XPP field and the transfer of the result to the latter, an opposite course is possible as well in that the hardware module may use the XPP field as a more flexible data processing element and/or where mixed forms are possible, that is, where data are shifted back and forth in ping-pong-like fashion or in a less regular manner for overall processing.

FIG. 6 a shows a variant in which again data are exchangeable via FIFO memories and in particular again FIFO memories are present either in the input branch and, preferably or also in the output branch. In addition, trigger vectors are now transmitted. Regarding the significance and application of trigger vectors, reference is made to WO 98/35299 (PACT08/PCT). The combination of identification information with programming information and/or trigger information or status information, which are exchanged in order to trigger certain data processing events or processes, should be mentioned once more explicitly.

FIG. 6 b shows that in the data exchange, a “time stamp”, that is, information regarding the temporal priority or the temporal validity of a data packet is transmitted as well. In the present case shown in FIG. 6 b, this transmission occurs in read-write memories (RAMs). The time mark that is co-transmitted may be used to select those data packets, which are to be processed next.

It should be pointed out that in this manner the data processing may be controlled particularly favorably. The actual procedure of transmitting time marks along with a data word or data packet in data flow processing was already described in WO 02/071249 (PACT18/PCTE, butcher protocol). Irrespective of the fact that document WO 02/071249 is in its full extent incorporated by reference for disclosure purposes, it should be pointed out explicitly that the assignment of a time mark to data packets allows for both a data sequence to be reconstructed and/or restored at any later time as well as for operands to be combined with each other as required, which is advantageous particularly if branches supplying operands are balanced with respect to the latencies.

It should be mentioned that in the manner in which for FIG. 6 b reference was made to WO 02/071249 (PACT18/PCTE), with the other figures reference is made to WO 02/071248 (PACT15/PCTE) and WO 02/071196 (PACT25/PCTE) for FIG. 5 a as well as WO 02/071196 (PACT25/PCTE) and WO 98/29952 (PACT04/PCT) for FIG. 5 b as well as WO 98/35299 (PACT08/PCT) and WO 02/071196 (PACT25/PCTE) for FIG. 6 a, and that all of the mentioned documents are respectively incorporated in their full extent individually and in combination for disclosure purposes.

It should be mentioned that incidentally the coupling methods mentioned and disclosed here are also combinable, for example by connecting a FIFO upstream to a RAM-PAE while co-transmitting time marks in parallel and the like.

It should be mentioned that as far as the physical connectability of the hardware modules is concerned, the latter may be connected either by integration into the internal bus system of the XPP or of another processor field and/or via external, possibly bundled input/output lines. The possibility should be pointed out of combining a multitude of individual input/output lines to form buses in order to obtain a coupling of the hardware modules for example in finely granular fields. In this connection, reference is made to WO 02/29600 (PACT22aII/PCTE) and the parallel patents connected with this by way of priority, which are all incorporated to their full extent for disclosure purposes.

With respect to the spatial arrangement of hardware modules or hardware parts of the present invention in XPP fields or other fields, FIG. 8 shows that these may be provided either as columns or lines at the edge of a field, it obviously also being possible for a field to be surrounded by such hardware modules or hardware parts, and/or that individual elements or field groups may be distributed over the field, as shown in FIG. 8 on the lower left. Alternatively it should be mentioned that a hardware element and/or a group of hardware elements according to the present invention could also be set next to an XPP field or other field or, assuming appropriate manufacturing processes, could be placed on top or underneath such a field. The usability by integration on a single, jointly manufactured chip should be disclosed as a possibility in the same manner as those of manufacturing the separate elements independently and connecting them. It is understood that in the variants in which the hardware modules of the present invention are connected most closely to the field because they form an interposed column, represent a column at the edge, a frame and/or elements provided in a field, the setup is preferably connected via internal buses, whereas in an arrangement next to the field a connection via I/O connectors is preferred. In the case of an arrangement on the edge, connections may be established alternatively via I/O ports and/or via internal buses. It should also be mentioned that bus lines or other lines may be drawn across the hardware elements that are set between field elements, if necessary. Hardware elements that are set into a field may also be connectable by separate lines, as required. The arrangement in columns is incidentally clearly preferred, a positioning of the column at the edge or in between being preferred depending on for what purposes a data processing unit having a hardware part of the present invention is to be used.

In a preferred variant, the number of hardware modules will be selected in such a way that on the one hand the data processing tasks to be performed may be solved quickly and efficiently, and that on the other hand the form factor is observed when inserting into or next to a field.

In this connection, it should be mentioned incidentally that the hardware modules of the present invention, even when closely coupled to a field, may additionally have separate I/O connections for communication with external elements such as memories and the like, if necessary.

According to FIG. 9, it is possible incidentally to allow for a connection between the hardware modules of the present invention among one another and/or certain field element parts, which is either permanently fixed, alternatively and preferably, however, is set up only temporarily. This is readily possible particularly when a hierarchically ordered bus system allows for global bus lines that may be set up and/or dismantled. Regarding the setup and/or dismantling of bus lines, reference is made by incorporation of its entire disclosure to the document WO 98/35294 (PACT07/PCT).

It should be pointed out that prior to building a mask for manufacturing a dedicated chip, recourse may be taken, if necessary, to an emulation, the hardware parts being emulated using FPGA. It is pointed out that the applicant has already proposed building XPP fields, in which PAEs are provided that may represent small FPGA fields. By suitable wiring of several such FPGA PAEs, the hardware structures may then be emulated, if indicated. It is then possible to emulate a verification or emulation of a personalized or customer-specific design by a suitably designed XPP test chip having FPGA PAEs.

While it was indicated above that hardware modules may be constructed by hyper PAEs arranged linearly one behind the other only by way of example, which are suitably parameterized and defined, this is not absolutely necessary. It may be advantageous not to assign to each operand combination in the program part a separate PAE and provide for a linear processing. Rather, in particular in especially complex program parts, it would also be possible to break up the program parts in turn into a multiplicity of different configurations to be processed in the hard module. In such a case, for example, it may be established, for example, that a certain cut for breaking up the program part into two configurations would be advantageous. The manner in which such cuts may be applied is known per se. Reference is made in particular to PCT/EP 02/10065 (PACT11/PCTE). If such a procedure is desired, typically the range of function of the hard module is selected to be such that the range of function at the desired place respectively corresponds to the set union of the operand combinations etc. executed or to be executed using different configurations. It should be pointed out that in a multi-configuration hard module definition, fixed configurations may be provided, if indicated, which are provided in a fixed manner in the hardware module, compare PCT/EP 03/08080 (PACT30/PCTE).

Further, it should be pointed out that if multiple configurations are to be processed successively on the hardware module, the ranges of function of the individual hard module areas, which are obtained by parameterization, that is, the definition of parameters of the hyper PAEs, are preferably selected to be such that respective computing units, considered individually, have still a minimal range of function. This may possibly occur in that the configurations that are divided are executed in such a way that multiplications are always performed in the same PAE if in each configuration only one multiplication is required, and, instead of a multiplier stage, in another PAE, the data lines to be addressed by a certain configuration, required for the return of data or the transmission of data, in particular lines to be implemented here too as next-neighbor connections, are implemented possibly at a lower surface area requirement. 

1. (canceled)
 2. A method for automatically generating at least a part of a hardware netlist of a chip, the method comprising: assembling a definition for a chip, the definition defining a plurality of hardware modules, wherein, for each of at least some of the defined plurality of hardware modules, one or more features of the respective hardware modules is selectable from a respective plurality of features by selection of one or more of a plurality of corresponding parameters, the definition not defining the parameter selection; transforming each of a plurality of algorithms into a respective form that is specific to execution on the defined plurality of hardware modules; for each of the defined plurality of hardware modules, determining required functionality of the respective hardware module based on the transformed algorithms; and for each of the defined hardware modules, in accordance with the determined required functionality of the respective hardware module, defining a respective selection of parameters from the respective plurality of corresponding parameters of the hardware module.
 3. The method of claim 2, wherein the defined parameter selection for each of at least one of the defined hardware modules, defines a selection of fewer than all of the plurality of corresponding parameters of the respective hardware module, such that at least one of the plurality of corresponding parameters of the respective hardware modules is not selected by the definition.
 4. The method of claim 3, wherein the parameter selections are performed to provide a minimal number of parameter selections.
 5. The method of claim 2, wherein the parameter selections are performed for optimizing at least one of a size of the chip, an operation speed, and a power dissipation. 